By Bruce Naegel, February 2017

Net Zero Emissions?

The North Bay Clean Energy Forum (NBCEF) recently wrote a paper on how to achieve the GHG reduction goals in SB 350 and AB 802 (1).  NBCEF used Net Zero Emissions instead of Net Zero Energy.  These are both valid approaches that have been defined by the NREL (National Renewable Energy Laboratory). It is worth discussing them since they lead to different ways on how to reduce GHGs (2).

Net Zero Energy

A Net Zero Energy building is one where the total amount of energy used by the building on an annual basis is equal to the amount of renewable energy created on the site (2). To achieve this one first makes the building as energy efficient as possible to minimize the amount of energy needed. One then puts up solar panels, fuel cells or other ways to generate electricity with low carbon.

SB 350 and Net Zero Energy.

SB 350 has two major components to the bill as currently revised. The first is to define the amount of California defined renewable energy to be at 50% by 2030 (3). The second is to double the energy efficiency increases for existing buildings. The first one is easily defined by renewable portfolio standards (RPS). While challenging, the pathway is defined and utilities are on their way to supplying this.

The goal of doubling energy efficiency increases in buildings is a bit more difficult to define. A search on the web for what the current energy efficiency increases for buildings is challenging. The CPUC / CEC has indicated they will release a definition of this in April of 2017. When this is released, one can look at standard energy efficiency methods in relation to doubling the energy efficiency standards. One can then see what can be done cost effectively on the existing building fleet to reduce energy consumption.

The Net Zero Emissions Approach

Net Zero Emissions starts out with the goal that the building does not emit GHGs instead of relating it to energy used. With this approach, one can drive the GHG content to near zero (Net Zero Emissions) by making all devices using energy electric and sourcing them with carbon free electricity. If the building is energy inefficient, it can still be Net Zero Emissions. The definition also includes transportation which is addressed by electric vehicles.  The three steps to getting to a Net Zero Emissions building are:

  • Source All  Electricity From A Zero-Carbon Electricity Supplier
  • Make All Energy Use In The Building Electric
  • Enable Electric Vehicles To Charge At Home.


Wind Turbines in Sonoma county

Source All Electricity From A Zero-Carbon Electricity Supplier

This is becoming easier to do as time marches on. California’s mandates call for a 50% renewable content by 2030 and an 80% renewable content by 2050 (4). The CCA / CCE movement is accelerating that movement with their offerings that are better than the California standards. Both the IOUs (Investor owned utilities) and the CCEs are currently offering zero carbon options at a higher price for concerned citizens. This says there are options today for Net Zero Emissions Electricity.


Net Zero Emissions
Heat Pumps are the efficient way to convert electricity to heat

Make All Energy Use In Buildings Electric or Renewably Powered.

Some buildings and homes today are all electric with electric heat, electric hot water, and electric cooking and laundry appliances. However, most the buildings in California are heated and supplied with hot water using natural gas. Hot water heaters and building heaters have a service lifetime. Hot water heaters have service life around 15 years.

Electric heat pump technology is the efficient way to use electricity to heat or cool. Heat pumps are available but expensive today. This is an area needing further development. Supporting heat pumps can be put into building codes for new buildings and major retrofits.  Special financing programs are needed for supporting them as retrofits to existing buildings.


Net Zero Emissions

Enable Electric Vehicles To Charge At Home.

Currently over 80% of electric vehicle charging occurs at home (5). This is the most convenient and allows one to take advantage of the low cost of electric power from 11 to 4 in the morning.  Building codes need to ensure that the conduit and wiring needed for electric vehicles is installed for major upgrades and new construction.  Making it easier to get individual charging in for existing buildings (permits, etc.) will also help.

Moving to Net Zero Emissions and Net Zero Energy

Making buildings more energy efficient will help lessen the demand for clean energy and lower the operating costs. What can be done cost effectively should be done and encouraged. New Appliances, LED light bulbs and weatherization will help but more will be needed.

The path of Net Zero Emissions can be taken today for those who can afford it and are committed. There are simple things that can be done to make heat pump deployment more widespread, including improving the supply of trained installation technicians and simplified / improved ordinances and permitting. Longer term, we need research and development of more efficient and cost effective heat pumps.

Accelerating the move to electric vehicles will happen in part as more affordable EVs with 200 + mile range become available. We also need a better charging infrastructure, especially at home. In the longer term, this means building codes that require new residential buildings and multi use buildings to put in the electrical infrastructure (conduit and wiring) to simplify electric chargers when available.


Picture Credits:

  • Wind Turbine picture from Pixabay
  • Heat Pump picture from Wikipedia article on Heat Pumps
  • Electric Vehicle Charging picture from Naegel